Process of obtaining ammonium sulfate from gases.



, N. CARD. PROCESS OF OBTAINING AMMONIUM SULFATE FROM GASES. APPLICATIONFILED JUNE 28, 1909.

952,560, Patented Mar. 22,1910;

In wen/60w i "5 m. 27. Mu.

-facture of sulfate.

OF E- mxonnmlcano, or k KOHLENZEQHE M I v l I t 'u PROCESSOF OBTAININGAI YLMONIUQM SULFATE FR p v Speciiicationof Lettersrateiit.[PatentedltIa iasnrmflenn v anr, Assr onoa T0 enwenitscnar'r him seemONT. cams, orsoniitennpcnammvv.

Ap tanaitiai ti 25, .1909. Serial n 504,818

To all whom it may concern:

Be it known that. I, Niiionnn'. Cane, asubject of the King .zof Prussia,resldiugat- QO-a lyleinekestrasse, Berlin, Germany, littV6 "'LIl--:.vented certanr new and useful Im-provements in ProcessesofObtainingAnnnonium Sulfate fIOlli'iiDlStlllfitlOlbGtlSES; andflI dohereby declare thezfollowing to be a'full,

clear, and exact description ofthe invention.

mg out the ammonia contalned in the gases with water, conducting-theammonia water into' distillation columns and utilizing the ammoniaderived therefrom for the manu- Attempts have been made to remove the"ammonia from the distillation asesdirectly'by means of sulfuric acid,buksu'ch' methods "were objectionable for thdfolloWihg reasons: If theammo- 'niacal. distillation gases were passed. into concentratedsulfuric acid, it is true that a solid-salt, ammonium sulfate, wasobtained, but there was also a severe action of the sulfuric acid on thegases themselves which occasioned the liberation of tar in a troublesomemanner; if the absorption solution contained but little free acid,however, there was no separation of tar, but there was also nodeposition of salt, so that the lye obtained had to be eva orated forthe purpose of obtaining the sa t, which operation entailed greatexpense.

Now according to a known process a rela tively slightly concentratedabsorption lye containin sulfuric acid is employed, but in order toirectly crystallize out the salt, 1t 1s necessary to prevent the steamcontained in the gases from condensin and to this end thegases aresuperheated again, after the separation of tar and steam. and beforethey ass into the absorption solution. Accordmg to the statement oftheinventor of said process, this superheating of the gas not only preventsthe condensation of the steam contained in the gases, but also preventsany further dilution of the absorption lye owing to steam condensing,when the ammonia saturated with steam is simultaneously conductedtheretofrom theammonia columns that work up the ammonia water which condensedduring the cooling operation of the gases: Practical experience withthis process has shown, on the one hand, that the su1)erheating. of thegases before" thcir' introduction into. theabsorption lye necessitates aparticularly troublesome apparatus and, on the other hand that this'supcrheating does not suflice to prevent'the condensation of theaqueous vapor whlch comes simultaneously from the ammonia columns intothe lye; consequently in this process there is either a continuousdilution of the absorption lye,

so that no solid salt is deposited, or 'the :superheatim inust be drivenso farthat the sulfate of ammonia is decomposed, this being noticeableat 90 C.

Now the object of my invention is to remedy these defects. According'tomy in ventionthe troublesome'superheating of the gas isom1tted,0n'the'one hand, and on the other-hand, solid salt isconstantl'ydeposited whereby the ammonia absorbed from the distillation gases andalso that ammonia which is obtained from the distillin column from theammonia water con ensed when the gases cool is bound in-one single absortion vessel. Thedistillation gas is code to a temperature of 15 to 20 C.and thus liberated from the tar, and simultaneously a part, about 1/5 ofthe ammonia contained in the gas, is separated with the water ofcondensation forming ammonia water. The ammonia-cal, cooled gas is nopassed without further heating into a solution of sulfate of ammonia,preferably into one of about 29-35 B6. which contains a smallpercentage, up to about 5%, of free sulfuric acid. That gas which isobtained by working up the ammonia contained in the condensed water, issimultaneously led with the cooled gas, but in a concentrated state,into this solution. In this manner the formation of solid salt in theabsorption lye is obtained without the lye becomin diluted. \Vhensupplying the concentrate ammonia gas to the absorption lye the heatproduced by the chemical action of ammonla on sulfuric acid suflices forpreventing the vapor from the distillation gas and also from the ammoniadistilling column from condensing without any special devices forsuperheatlng the mixture of steam and ammonia being necessary.

The concentrated ammonia gas is preferably obtained from the gases ofthe ammonia column apparatus in the usual manner by passin these wastegases throu h a cooler or con enser and cooling them om 40 to 60 C. Inthis manner not only is the ammonia gas concentrated, but also steam isseparated so that this no longer prejudicially influences theconcent-ration'of the absorption lye. I therefore, obtain a solid salt,free from tar, from the absorption lye and when the gas is worked upaccording to my process, ammonia washers are done away with, the work inthe ammonia works is reduced by about? 5%, and the quantity of-Wastewater is diminished by 75%.

In order that my invention may be more fully understood I will describethe same in connection with the accompanying draw ing illustrating theapparatus for, carrying out my novel process in elevation and partly. insection.

The gases from a coke oven, gas retort or similar apparatus, not shown,are drawn through pipe a and a cooler 0, of any suitable construction by.a pump 6 which pump at its forcing side is connected by a pipe 2 to atar separator cl of any well known construction, From "the tar,separator thecooled gas" passes through pipes 3 and 4 to, theabsorptlondevice 0 also of an suitable and well known construction w ichcontains the described acidulated ammonium sulfate solution.v Thecondensates'from the.

cooler 0 pass by pipe 5 to a reservoir 7 and are taken from here by pipe6 and pump 7v or any other suitable means, and forced. through pipe 8;to the distilling column g.

The vapors from column 9 being a mixture I of water-vapor and ammonia,pass by pipe 19 to: the cooler h of any suitable construction, arepartially dried and then passby pipe 10 into the absor tion device esimultz'meously-with the dried distillation gases. -'The condensate incooler k r turns gases. which comprises cooling the gases to separatefrom them tar and ammonia water, distllllng the ammonia water, partiallydrying the vapors therefrom and mixing them with the previously cooleddistillation gases and conducting the mixture into a solutioncontainingammonlum' sulfate and sulfuric acid. v a 2. The process ofobtaining-splid ammonium sulfate from ammoniacal distillation gaseswhich comprises cooling the gases to separate from them tar and ammoniawater,

distilling the ammonia water, separating water from the resulting vaporsand simultaneously conducting these vapors withthe previously cooleddlstillation gases into a solution of ammonium sulfate containin aboutfive percentum of sulfuric acidv and of from twentynine to thirty-fivedegrees Baum in'strength.

In testimony that I claim the foregoing:

as my invention, I have signed my namein presence of two subscribingwitnesses. NIK, DEM CARO.

Witnesses:

,HErmY HAsPER, 3 WOLDEMAR Ham.

